/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/GroupTopology.h
a 3D frame for the given selection
[FFrame3d](API\Runtime\GeometryCore\FFrame3d_1) GetSelectionFrame ( const [FGroupTopologySelection](API\Plugins\DynamicMesh\FGroupTopologySelection) & Selection, [FFrame3d](API\Runtime\GeometryCore\FFrame3d_1) * InitialLocalFrame ) const